Current commercial transport aircraft typically include deployable high lift devices that change the aircraft wing shape depending on flight conditions. These devices can include leading edge flaps and/or slats, and trailing edge flaps that are extended to increase lift during takeoff and landing, and stowed during cruise to reduce aircraft drag. Commercial transport aircraft can also include spoilers to selectively reduce lift during descent, landing, roll maneuvers and aborted takeoffs.
FIG. 1A is a partially schematic, cross-sectional illustration of a wing 110 configured in accordance with the prior art. The wing 110 can include a trailing edge 111, a forward flap 120a extending aft of the trailing edge 111, and an aft flap 120b extending aft of the forward flap 120a. A mechanical linkage arrangement 122 couples the forward flap 120a and the aft flap 120b to an actuator 121. FIG. 1B illustrates the aircraft wing 110 with the forward flap 120a and the aft flap 120b deployed to produce a high lift configuration. In this configuration, the flaps 120a, 120b can form a forward flap gap 124a and an aft flap gap 124b that provide for controlled, attached flow over the forward flap 120a and the aft flap 120b, respectively. Accordingly, this double-slotted wing configuration can effectively provide high lift for a large transport aircraft during takeoff and landing (when the flaps 120 are deployed) and can have a substantially reduced impact on aircraft drag (when the flaps 120 are stowed).
One potential drawback with the wing 110 shown in FIGS. 1A and 1B is that the mechanical linkage arrangement 122 is relatively complex and can therefore be heavy and somewhat costly to build and operate. Accordingly, other less complex arrangements have also been developed for providing large aircraft with a high lift capability. One such arrangement is disclosed in U.S. Pat. No. 4,120,470, assigned to the assignee of the present invention. The '470 patent discloses a single trailing edge flap and a spoiler that controls the size of the gap between the single trailing edge flap and the wing. This arrangement is simpler than the arrangement described above with reference to FIGS. 1A and 1B because the single flap requires fewer moving parts than a double flap arrangement. However, this arrangement employs a flexible panel and a spoiler actuator that is integrated with the flap actuation mechanism. In some cases, these features can increase system complexity and weight, while reducing system versatility.